Investigating the origin and tissue concentration of polycyclic aromatic hydrocarbons in seafood and health risk in Niger Delta, Nigeria

Abstract

The origin, tissue concentration, and health risk of polycyclic aromatic hydrocarbons (PAHs) contaminants in three economically important species of seafood, including catfish (Chrysichthys nigrodigitatus), prawns (Macrobrachium macrobrachium), and periwinkles (Tympanotonus fuscatus) from the crude oil-impacted Niger Delta region, were investigated. The concentrations of PAHs were measured by coupled gas chromatography-mass spectrometry after repeated extraction by ultrasonication in hexane and cleaning up in silica gel. The origin of PAHs was deduced using established mathematical protocols. Health risk from the consumption of contaminated seafood was evaluated for 60 kg bodyweight individuals at a fish consumption rate of 36.94 g per person per day. Different tissue concentrations of PAHs residues at low, moderate, and chronic levels were revealed. Mean total PAHs varied from 4.55 to 6.36 mg kg⁻¹ in catfish, 4.61 to 7.75 mg kg⁻¹ in prawns, and 4.91 to 6.14 mg kg⁻¹ in periwinkles. The tissue concentrations were high above PM_2.5, enough to suspect PAHs-related health risk, especially among residents who consume a large quantity of seafood. Carcinogenic PAHs index, benzo[a]pyrene, varied from below instrument detection (<0.01) to 0.29 mg kg⁻¹. The estimated carcinogenic potency equivalent concentrations (PEC) of PAH varied from 0.653 to 2.153 above the screening value (SV), 0.01624 in the three species investigated. Mathematical evaluation and dominant tissue concentration of high molecular weight PAHs in all the seafood investigated showed pyrogenic origin of PAHs.